Page 4 - Microsoft Word - Lesson note-HYDROGEN

Water containing soluble salts of calcium and magnesium in form of hydrogen
carbonate, chlorides and sulphates is called hard water.

Temporary hardness in water is due to soluble salts of hydrogen carbonates
of magnesium and calcium.

Permanent hardness in water is due to soluble salts of chlorides and
sulphates of calcium and magnesium.

Temporary and permanent hardness of water can be removed by the use of
zeolites, and synthetic ion-exchangers.

Heavy water, D2O is another important compound which is manufactured by
the electrolytic enrichment of normal water. It is essentially used as a
moderator in nuclear reactors.

Hydrogen peroxide, (H2O2) has an interesting non-polar structure and is widely
used as an industrial bleach and in pharmaceutical and pollution control
treatment of industrial and domestic effluents.